Pushbutton rotary switch having unitary actuator



March 26, 1968 J. P. BARRETT ET AL 3,375,337

PUS HBUTTON ROTARY SWITCH HAVING UNITARY ACTUA TOR Filed Jan.

0R5 BARRETT T. SLATTERY NORRIS JAMES P EDMUND JOHN H. WWM

ATTORNEYS United States Patent Ofiice 3,375,337 PUSHBUTTON ROTARY SWITCHHAVING UNITARY ACTUATOR James P. Barrett, West Hartford, Edmund T.Slattery,

Hartford, and John H. Norris, Haddam, Conn., assignors to VeederIndustries Inc., a corporation of Connecticut Filed Jan. 5, 1966, Ser.No. 518,916 Claims. (Cl. 200156) ABSTRACT OF THE DISCLOSURE Switchcomprising a housing and a rotary brush supported therein, a printedcircuit board supported on said housing in perpendicular relation to therotational axis of the rotary brush, the rotary brush having contactscarried thereon in contact with the printed circuit board, and a unitaryactuator including a double drive pawl and ratchet wheel subassemblydrivingly connected to the rotary brush for selectively orienting thecontacts relative to the printed circuit board to establish a desiredelectrical circuit connection.

This invention relates to switches and particularly concerns switchesfor controlling a plurality of electrical circuits.

A primary object of the invention is to provide an improved switch whichis quick and easy to operate and is of notable use in selectivelysetting a plurality of circuit connections in an electrical controlsystem.

Another object is to provide an improved switch particularly suited forminiaturized application in conjunction With a printed circuit plate.

A further object of the invention is to provide an improved switchhaving a minimum number of parts and incorporating a push button driveof compact integral construction for establishing a preselected circuitconnection.

Another object of the invention is to provide an improved switch whichis economical to manufacture and assemble in an easily installed modularunit and which is capable 'of providing long reliable service virtuallyfree from maintenance requirements.

Other objects will be in part obvious and in part pointed out more indetail hereinafter.

The invention accordingly consists in the features of construction,combination of elements and arrangement of parts which will beexemplified in the construction hereafter set forth, and the scope ofthe application of which will be indicated in the appended claims.

In the drawings:

FIG. 1 is a side view, partly broken away, showing a preferredembodiment of a switch constructed in accordance with the invention;

FIG. 2 is a sectional view, partly broken away, taken generally alongline 22; and

FIG. 3 is an isometric view of an actuator incorporated in theinvention.

Referring now to the drawing in detail, a switch of the invention isshown as having a housing which includes a rectangular side panel 11 andan outwardly projecting wall 12 extending around its peripheral edges.The housing 10 is closed by a printed circuit plate 14 removably mountedthereto in oppositely facing relation to the side panel 11. A series ofconductors, illustrated in phantom at 16 on the inside surface of theprinted circuit plate 14, are connected to an associated electricalcontrol system, not shown.

A pair of bridging contacts 18, 19 are carried on a rotary brush 20illustrated as being mounted adjacent the printed circuit plate 14 toone side of a ratchet wheel 3,375,337 Patented Mar. 26, 1968 22supported for rotation on a support shaft 24. The rotary brush 20comprises a pair of V-shaped arms 26, 28 interconnected to extend inopposite directions. The arms 26, 28 are of equal length and are mountedto the ratchet Wheel 22 in eccentric relation to its rotational axis.The contacts 18, 19 are fixed on the extremities of the arms 26, 28which are biased axially outwardly of the ratchet wheel 22 for engagingthe printed circuit plate 14.

It will be understood that the conductors 16 may be arranged in anysuitable manner on the printed circuit plate 14 to provide fixedcontacts which, in conjunction with the movable contacts 18, 19 of therotary brush 20, provide a switching action to change the circuitconnections of an electrical control system. A number wheel 30 isdrivingly connected to the ratchet wheel 22, and suitable indicia isprovided on the number wheel 30 corresponding to predetermined angularpositions of the rotary brush 20 relative to the printed circuit plate14. The resulting circuit connections of the electrical control systemthus may be readily determined by a visual reading of the correspondingindicia appearing in window 34 in front of the housing 10.

In the specific embodiment, the number wheel 30 is rotatably mounted ona shaft 38, and rotational movement of the ratchet wheel 22 istransmitted to the number wheel 30 by meshing spur gears 40 and 42. Spurgears 40 and 42 are mounted on shafts 24 and 38 adjacent the side panel10 and respectively formed in integral coaxial relation to the ratchetwheel 22 and the number wheel 30. The rotary brush 20, which is asindicated above is biased against the printed circuit plate 14, assistsin retaining the ratchet wheel 22 in proper position on its supportshaft 24, and any suitable stabilizing means may be used to retain thenumber wheel 30 against axial movement on its shaft 38.

So that the rotary brush 20 may be moved to preset and electricalcircuit connection as determined by a visual reading of the number wheel30, an actuator 44 is provided having a pair of driving pawls 46, 48engaging diametrically opposed portions of the ratchet wheel 22 foralternately driving it in one angular direction through a series ofswitch positions. The drive pawls 46, 48 are respectively mounted on theends of a pair of flexible fingers 50, 52 which are cantilever supportedon an upright pawl support portion 54 of the actuator 44. The base ofthe pawl support portion 54 is integral with an inner end of anelongated arm portion 56 mounted for reciprocating movement in the lowerpart of the housing 10. The flexible fingers 50, 52 project outwardlyfrom the pawl support portion 54 in the same direction in parallelspaced relation to the arm portion 56 for supporting the 'drive pawls46, 48 respectively on upper and lower portions of the ratchet wheel 22.

The arm portion 56 of the actuator 44 is mounted for sliding movement ona pair of upstanding lugs 60, 62 in the lower portion of the housing 10,and a slotted opening 64- is provided in the arm portion 56 at its innerend for receiving a guide 66 projecting outwardly from the side panel11. The guide 66 and the slotted opening 64 cooperate to maintain thearm portion 56 in proper alignment and prevent it from moving up anddown within the housing 10. The outer end of the arm portion 56 isprovided with an extension 68 of reduced size extending through anopening in a front panel 70 of the wall 12. The exten sion 68 serves toprovide a manually operable push button 74 positioned externally of thehousing 10, and minimum peripheral clearance is provided between theextension 68 and the opening in the front panel 70 to minimize any freemovement between the actuator 44 and the housing 10.

The actuator 44 is limited to reciprocating rectilinear movement betweena first or right-hand position shown in the drawing, and a second orleft-hand position, wherein the inner end of the arm portion 56 engagesa back panel 76 of the wall 12. Side-to-side movement of the actuator 44is minimized by the provision of a projection 78 extending laterallyoutward of the pawl support portion 54- to, continuously engage theprinted circuit plate 14. To retain the actuator 44in itsright-handposition wherein the drive pawls 46, 48 maintain the ratchetwheel 22 against reverse turning, one end of a coil spring 80 is seatedin a recess 82 in the back panel7 6 and its opposite end is seatedagainst the pawl support portion 54. The coil spring 80 is maintained inproper position by a post 34 projecting from the panel support portion54 coaxially within the coil spring 80. Thus, it will beseen that theactuator 44 is continuously biased by the coil spring 80 toward .itsright-hand position to maintain the rotary brush in a selected switchposition even though the customary no-back pawl has been eliminated bythe above described unitary structure of the actuator 44.

To prevent overthrow of the ratchet wheel 22 by the drive pawls '46, 48during its rotation from one angular position to the next, a stop 86protrudes from an arcuate inner face 88 of the pawl support portion 54for engaging the ratchet wheel 22 when the actuator 44 is in its normalright-hand position. In this position, the inner face 88extendscircumferentially about a portion of the ratchet wheel 22intermediate the flexible fingers 50, 52.

By virtue ofthe above described structure, the switch of the inventionis adapted for miniaturized application whereinthe unitary constructionofthe actuator 44 inherently provides self-aligning, guiding andstopping features while serving to drive the rotary brush 20 through aseries of switch positions and to firmly maintain it in a selectedswitch position. Moreover, the actuator 44 is particularly suited to bemolded as a single unit of suitable plastic such as Delrin so as'toassure low cost manufacture 'and' assembly.

To briefly summarize the operation of the switch, the circuitconnections of the electrical'control system may be selectivelychangedmerely by depressing the push button 74 to move the entireactuator 44 into the left-hand position in opposition of the force ofthe coil 'spring- 80. This causes the upper drivepawl 46 to positivelydrive the ratchet wheel 22 in a counterclockwise direction while thelower drive pawl'48 isflexed downwardly to slip over the'teeth on theopposite side of the ratchet wheel. Upon releasing the push button 74,the actuator 44 automatically returns to its normal right-hand positionunder the force of the coil spring-80 to cause the lower drive pawl 48to rotate the ratchet wheel 22 counterclockwise while the upper drivepawl 46 flexes upwardly and'slips over the ratchet wheel 22. The drivepawls '46, 48 thus alternately advance the rotary brush 20 fromoneangular position to the next in two half step movements of theratchet'wheel 22 in response'to a two stroke reciprocating movement ofthe actuator 44 thereby to change the circuit connections of theelectrical control system as indicated by a visual reading ,otthe numberwheel 30.

Itwill be obvious that the above described switch can be combined withothers to provide a stack or bank of modules, e.g., for linking a numberof electrical control systems. Overt-hrowof the-ratchet'wheel "22 iseffectively prevented by the'stop and reverse turning is eliminatedby'the' 'double drive pawl and ratchet arrangementwhereby the electricalconnection can'be changed only when the actuator 44 is operated toreciprocate between its right and lefthand positions. The switch of theinvention is quick and easy to operate and provides a positive drivingaction which is obtained in a structure requiring a minimum numberofparts economcal to manufacture and assemble.

from the spirit and scope of the invention, the scope of which isdefined in the appended claims.

We claim:

1. A switch comprising a housing, switching means provided in saidhousing for controlling a plurality of electrical circuits and includinga rotary brush mounted in said housing, a printed circuit boardsupported on said housing in perpendicular relation to the rotationalaxis of said rotary brush, and contacts carried on said rotary brush incontact with said printed circuit board, a ratchet wheel supported forrotation in said housing, a driving connection between said rotary brushand said ratchet wheel, and an actuator mounted in said housing foroperating said ratchet Wheel, said actuator having integral therewith apair of flexible fingers having spaced opposed free ends and a pair ofdrive pawls fixed thereto, said drive pawls engaging diametricallyopposed portions of saidratchet wheel to alternately drive the same inone angular direction for selectively setting electrical circuitconnections in accordance with the angular position of said rotary brushrelative to said printed circuitboard.

2. The switch of claim 1 wherein said actuator includes an arm portionmounted for reciprocating recti-. linear movement in said housing andcooperating therewith to establish first and second positions limitingthe movement of said actuator in opposite directions, a pawl supportportion having one end integral with said arm portion, said flexiblefingers being cantilever supported on said pawl support portion, saiddrive pawls being fixed to said free ends of said flexible fingers formovement parallel to the axis of movement of said arm portion thereby toprovide a unitary actuator for alternately driving said ratchet wheelfrom one angular position to the next in two half step movementsresponsive to a two stroke reciprocating movement of said arm portionbetween the first and second positions, an a stop protruding from saidpawl support portion intermediate said flexible fingers, said stopengaging said ratchet wheel when said actuator is in the'first positionto prevent overthrow of said ratchet wheel by said drive pawls duringits movement from one angular position to the next.

3. The switch of claim 2 wherein said flexible fingers project in thesame direction from said pawl supportportion in parallel relation to theaxis ofmovem'ent of said arm portion.

4. The switch of claim 2 wherein said arm portion of said actuatorincludes an extensionat one endthereof projecting through an opening insaid housing to provide an externally positioned push button foroperating said ac tuator, and wherein a coil spring is-seated betweensaid housing and said actuator continuously urging the same toward thefirst position whereby upon actuating said push button, said actuatormoves to the second position in opposition to the face of said coilspring and upon releasing said push button, said actuator automaticallyreturns under the force of said coil spring to the first position.

5. The switch of claim 1 further including a number wheel supported forrotation in said housing and a window therein to permit viewing of saidnumber wheel, and a driving connection between said ratchet wheel andsaid number wheel whereby said number whert. provides a visual readingof a predetermined angular position of said rotary brush with respect tosaid printed circuit board.

References Cited UNITED STATES PATENTS 2/1958 Carlson et al 200-156 XFOREIGN PATENTS 199,880 11/1965 Sweden. 579,483 7/1958 Italy.

